Heat exchanger for fluids



Jan. 1, 1935.. H FELDMEIER 1,986,192-

HEAT EXCHANGER F OR FLUIDS Filed NOV. 4, 1953 2 Sheets$heet l Jan. 1,1935'. ,"H FELD EIER HEAT EXCHANGER FOR FLUIDS 2 Sheets-Shet 2 [WKF0792.

Patented Jan. 1, 1935 PATENT OFFICE HEAT EXCHANGER Fon. mums HarveyFeldmeier, Little Falls, N. Y., assignor to Cherry-Burrell Corporation,Wilmington, Del,- a corporation of Delaware Application November 4,1933, Serial No. 696,658

'10 Claims.

This invention relates to improvements in heat exchangers for fluids orliquid heaters and coolers of the surface type, in which a liquid, forexam.-

' ple, milk, is caused to flow in thin films or layers over the outersurfaces of tubes or hollow heat exchange elements, to be cooled orheated by a cooling or heating medium circulating within the tubes orhollow'elements. While this invention is particularly applicable to milkcoolers and heaters, it is not limited to such use, but applies also toheat exchangers for other liquids. Well known surface milk heaters orcoolers comprise a series of horizontal tubes arranged one above another1 or in a vertical bank with connections for circulating a heat exchangemedium, such as cold or hot water or brine therethrough, a liquiddistributor or device arranged to discharge milk to be cooled or heatedonto the uppermost tube of the bank so .that the liquid will flowdownfwardly in thin films or layers over the outer surfaces of the tubesin succession into a trough or receiver at the bottom of the bank oftubes, the milk in-its passage over the tubes being cooled or heated bymeans of the heat exchange medium circulating through the tubes.

It is desirable in such devices to prevent the liquid being treated fromspreading or flowing lengthwise on the'tubes to their exteme ends oronto the headers, return bends or circulating connections for the heatexchange medium, in order to avoid waste of the liquid by dripping on oroutwardly beyond'the ends of the bottom receiver, and also to preventcontamination of the liquid by contact with possible condensation orleaking heat exchange medium on or from the headers or circulatingconnections. For this purpose, surface heat exchangers of this type havebeen provided with curbs or parts adjacent the ends of the tubes orspaced inwardly from the headers or circulating connections forlimitingthe flow of the liquid the surfaces of the tubes, which collars orstrips are soldered. brazed or welded to the tubes. 'llhese previousconstructions are objectionable in various respects. In the past, whenit was the practice to make the heat exchanger tubes or ele ments oftinned copper. the curbs could be conveniently soldered on the -tubes orelements; but

' the stainless steel and other stainless alloys now demanded by thetrade and commonly employed in the manufacture of surface heatexchangers are dimcultto solder or braze and, furthermore,

solder disintegrates in time and becomes porous and unsanitary.Therefore, when the heat exchangers are made from stainless steel ormaterials which do not solder or braze well, it has been essential to ahigh grade product to weld the curb rings or strips to the heat exchangetubes or elements. Weldingor brazing operations are slower and moreexpensive-than soldering, and if brazing or welding is used,considerable expense is entailed in grinding the corners to make smoothfillets to meet sanitary, requirements, particularly in the case of milkheaters or coolers, thus materially increasing the cost of the devices.

One object of my invention is to provide a practical and desirable heatexchanger of the sort mentioned which avoids the above. noted0bjections. I

Other objects of the invention are to provide a surface heat exchangerfor liquids having means of simple and inexpensive construction whichwill effectively limit the flow or spreading of the liquid lengthwise onthe heat exchange surfaces so as to prevent the liquid from being wastedor reaching the headers or circulating connections for the heat exchangemedium, and'prevent contamination of the liquid by contact withcondensation or leaking heat exchange medium; and also to provide a heatexchanger for liquids having theother features of improvement andadvantage hereinafter described and set forth in the claims.

The accompanying drawings illustrate different practical embodiments ofmy invention. In said drawings:

Fig. 1 is a front elevation, partly in section, of a tubular liquidheater or cooler of one form embodying the invention.

Fig. 2 is a transverse section of the upper por tion thereof, on anenlarged scale on line 2-2, Fig. 1.

Fig. 3 is a fragmentary front elevation on an enlarged scale, showing aslightly modified construction.

Fig. 4 is a fragmentary front elevationppartly in section, showinganother modification of the invention. 4

In the embodiment of the invention illustrated in Fig. I, the devicecomprises a number of substantially horizontal tubes 10 arranged in avertical bank. or one above another, a liquid distributingtrough'ordevice 11 arranged above the tubes and adapted todischarge the liquidonto the top tube so that"; will flow downin thin films over [the outersurfaces of the several tubes into the bottom trough or receiver 12arranged below the tubes. The tubes may be provided with the usuallongitudinal drip strips 10a along their bottoms, and the first or toptube of each bank or section is preferably provided with a drip strip10b along its top, as shown in Figs. 1 and 2. As shown, the tubes arearranged in two superposed sections or units, one above another, so thatthe liquid will first flow over the tubes-of one section to be cooled orheated by a medium flowing through these tubes and then flow over thetubes of the next section to be further cooled or heated by a colder orhotter medium, as the case may be, flowing through the'tubes of thelower section. But,

insofar as this invention is concerned,- the tubes can be arranged in asingle section, or 'in a plurality of sections, and in a single orplurality of banks.

Any suitable means or connections may be provided for circulating thecooling or heating medium through the tubes. As shown, the tubes 10 ofeach section are connected at their ends by suitable headers or returnbends 13 to form a continuous coil or conduit so-that a medium admitted,for instance, to the bottom tube of the section through an end inletpipe or connection 14, will flow in succession through the several tubesof this section and discharge through an outlet pipe or connection 15 atone end of the top tube of the section. Theheaders may be constructedand connected with the ends of the tubes either permanently orremovably, in any suitable manner. For instance, as shown in Fig. 1, theheaders 13 are permanently attached to the tubes, but they can be of anyother suitable or known construction, such for example, as illustratedin Fig. 4, in

which the tubes are secured at their ends in a common header 16 which ispartitioned to provide chambers 17 communicating with corresponding endsof "adjacent tubes so as to connect the tubes one with another inseries. The header has threaded openings in its outer wall which, asusual, are closed by removable screw plugs 18.

Each of the tubes 10 is straight and horizontal for the major portion ofits length, but is bent or made so as to form an upbent or upwardlyextending portion 19.at each end of the tube which preferably slopesupwardly and outwardly at a slight angle of about ten degrees, to thehorizontal portion of the tube. The tubes being oi. substantially equallength, the upbent or sloping portions 19 at corresponding ends of theseveral tubes are disposed vertically one above another and so that thebends or angles between the horizontal and upbent portions of the tubesare in vertical alinement one above another, and preferably in avertical plane, which is disposed inwardly from the adjacent end wall ofthe bottom trough or receiver 12.

The liquid distributor 11' may be oi. any known or suitable constructionadapted'to cause the liquid to flow downwardly in thin films over theouter surfaces of the tubes. The liquid films tend to spread out orflowlengthwise along the tubes but the films being thin, the upbent endsof the headers joining the'ends o! the tubes. T1113, the

liquid is prevented from being wasted by dripping off the heat exchangesurfaces outwardly beyond the ends of the bottom trough or receiver, andalso from reaching the headers or return bends or joints between thesame and the tubes.

The tubular section, .or sections, in case more than one section isused, together with the liquid distributor and the bottom trough orreceiver may be mounted in the stated relation in any suitable manner.Asshown, the endwise projecting outlet pipe or connection 15 at one endof the top tube of each section and a corresponding endwise projectingpart 20 provided at the opposite end of the section, bear on brackets 21fixed on upright supporting posts 22 at the opposite ends of the device.The bottom trough or receiver 12 is similarly supported by projections23 at its ends resting on brackets 24 fixed on the lower portions of theposts 22. The distributor 11, as shown, is provided at its ends withlegs 25 which are removably secured, as by thumb screws 26 to lugsformed on the-top headers at the opposite ends of the tube, and an outerleg 29 which slopes downwardly toward the header, return bend orcirculating connection at that end of the tube. These ofiset portionsthus have parts sloping upwardly in opposite directions to the crests orhighest points of the offsets.

bent ends 19 in the Fig. 1 construction, to prevent the creeping orflowing of the filmsoutwardly or toward the ends of the tubessubstantially beyond theanglesbetween these sloping parts and thehorizontal portions of the tubes, and the inwardly and upwardly slopinglegs prevent any liquid films which may be on the extreme ends of thetubes or the headers from flowing or creeping inwardly along the tubes.Thus, if there should be any liquidon the extremities of the tubes,headers or circulating connections, due either to condensation orleakage of the heat exchange medium through faulty joints between thetubes and the headers, return bends or circulating connections, suchliquid would be prevented from creeping inwardly along the tubes intocontact with the films of liquid being treated on the horizontalportions of the tubes. In other words, the upwardly offset portionsprevent films of liquid on the tubes at opposite sides of the crests ofthe ofisets from creeping or flowing into contact with each other so asto permit contamination of the liquid being treated by mixture orcontact with any heat exchange medium or condensation on the endportions. of the tubes, or the headers or circulating connections.

In each of the different embodiments of the invention illustrated, theupbent or oflset portions of the tubes which curb or limit the endwiseflow or creeping of the liquid on the tubes, are formed by integralportions of the tubes themselves. and no curbs or parts are used whichhave, to be attached or secured to the tubes by soldering, welding orotherwise. 1

An additionaladvantage of. the described tube construction is that someexpansion and contraction, due to unequal temperatures, is possiblewithout harm or objectionabledistortion .ot the device, since the benttubes are allowed a chance The upwardly and outwardly sloping legs oftheofisets act like the upto straighten or bend more without unduestrain on the connected parts.

I claim as my invention": 3

1. A surface heat exchanger for fluids comprising a tube arrangedsubstantially horizontally for a liquid film to flow over its outersurface transversely to the length of the tube for heat exchange with amedium within the tube, said tube having an upbent portion for limitingfilm flow lengthwise on the tube.

2. A surfaceheat exchanger for fluids comprising a'tube arrangedsubstantially horizontally for a liquid film to flow over its outersurface transversely to the length of the tube for heat exchange with amedium within the tube, said tube having an upwardly oifset portion forpreventing contact prising a tube arranged for aliquid film to flow overits outer surface transversely to the length of w the tube for heatexchange with a medium within the tube, said tube having a horizontalportion and a portion sloping upwardly from an end of said horizontalportion.

5. A surface heat exchanger for fluids comprising a tube arrangedsubstantially horizontally for a liquid film to flow over its outersurface transversely to the length of the tube for heat exchange with amedium withinthe tube, said tube having a shallow Ashaped portion forlimiting film flow lengthwise on the tube.

6. A heat exchanger for fluids comprising horizontal tubes arranged oneabove another, means offset portions.

for causing a liquid to flow downwardly exteriorly over said tubes, andconnections for circulating a heat exchange medium through said tubes,said tubes having portions thereof extending upwardly for limiting theflow of liquid lengthwise on the exteriorsof the tubes.

7. A heat exchanger for fluids comprising horizontal tubes arranged oneabove another, means for causing a fluid to flow downwardly exteriorlyover said tubes, and connections for circulating a heat exchange mediumthrough said tubes, said tubes having *upwardly sloping end portions forlimiting the flow of liquid lengthwise on the exteriors of the tubes.

i}. A heat exchanger for fluids comprising horizontal tubes arranged oneabove another, means for causing a fluid to flow downwardly exteriorlyover said tubes, and connections for circulating a heat exchange mediumthrough said tubes, said tubes having upwardly offset end portions forpreventing contact of liquid on the exteriors of the tubes at oppositesides of the crest of said 9. A heat exchanger for fluids comprisingtubes arranged one above another and having horizontal main portions andintegral portions which extend upwardly from said main portions and arein substantial vertical alinement, means for causing a liquid to flowdownwardly exteriorly over said horizontal main portions of the tubes,and connections for circulating a heat exchange medium through thetubes.

10. A heat exchanger for fluids comprising a pair of headers with fluidpassages therein, and horizontal tubes having upbent'ends secured to theheaders in communication with said passages, whereby liquid filmsflowing over the outside surfaces of the tubes are confined to thehorizontal parts of the tubes.

